Known in the state of the art are various plugs or elements used to seal orifices made in vehicle body plates or in other components.
Specifically, the state of the art includes plugs consisting of a pan-like body with an outer wall provided on its outer face with a peripheral upper flange and a peripheral bottom flange that are opposite each other and diverge in opposite directions, determining an intermediate space for receiving the plate in which the orifice to be sealed is made.
An example of this can be seen in Spanish invention patents ES2006404 and ES2097565, which describe a plug with an elastic closure having characteristics meant to increase tightness, for which purpose it is provided with a heat-deformable gasket and legs for attaching the lid.
There are also numerous antecedents seeking a proper seal and great tightness in the closure of the plug in the orifice to be sealed, which is achieved by incorporating in the plug a material that melts, such as of the type known as a “hot melt adhesive”, as can be seen in the plugs described in ES2125148, ES1022542U, ES2 240 676 EP631923, EP779203 or WO 2010/149237.
However, these have a drawback in that they can only be used to seal orifices of a specific nominal diameter, which means that it is necessary to manufacture different plugs to seal orifices of very similar diameters, such as 38 and 40 mm., which in addition to increasing manufacturing costs also creates the problem of increasing the stock of the factory or company that installs the plugs.
To solve this drawback there exist improved plugs which, to allow using them for different orifice diameters, incorporate elements that allow centering them in the orifice to be sealed. For this purpose, as in the example of U1067533, the outer wall of the plug body is provided on its inner face with rigid centering ribs that run vertically from the bottom end to the upper end of said inner wall.
In this way, after a certain length of the plug has been inserted in the orifice, the bottom flange, which has been folded upward due to its contact with the perimeter of the orifice, is released from the plate and acts due to its divergent configuration against the inner surface of the plate, ensuring that the plug is retained in the assembled position.
However, although these centering ribs do facilitate centering the plug in the hole, and thus allow this plug to be used with orifices of different diameters, the behaviour of these ribs can sometimes complicate the installation of the plug.
This difficulty arises because when the plug is inserted in the orifice, the plate must overcome the resistance of the lower lip, which meets the centering rib located on the outer face of the inner wall, hindering the installation.
This difficulty is further increased when the bottom flange also incorporates a hot-melt adhesive that helps sealing its upper face, which contacts the plate, as this melting material, before melting, increases the rigidity of the bottom flange whose resistance must be overcome when the plug is inserted in the orifice to be sealed; as explained above, this resistance is considerable, due to the presence of the centering rib that said lower lip meets.
In addition to the above, the presence of said melting material on the upper surface of the bottom flange makes the space between said lip and the centering rib even smaller, that is, it reduces the path that the lower flange has before it gives when the plug is inserted in the plate, attempting to overcome said lower flange so that the plate is located between said flange and the upper flange.